Japanese Patent Laid-Open Publication Nos. 2008-98931 and 2008-172496 disclose a technology for performing inter-vehicle communication using DSRC between automobiles. With the use of such inter-vehicle communication, when, for example, an automatic driving system including a preceding vehicle and a following vehicle is established, transmission of travel information of the preceding vehicle such as, for example, a vehicle speed, a steering angle, and an acceleration or deceleration, to the following vehicle is enabled by performing the inter-vehicle communication between the following vehicle and the preceding vehicle, and as a result, a proper automatic driving control may be implemented in the following vehicle. Since the DSRC may be applicable to road-vehicle communication, information obtained from the road-vehicle communication and information obtained from the inter-vehicle communication may be combined with each other so as to implement a more effective automatic driving control.